Julie Bishop has placed Australia firmly in Britain’s corner in the escalating row with Russia over the nerve agent attack on a former Russian spy on UK soil.

The British prime minister, Theresa May, expelled 23 Russian diplomats, among other measures, after saying the Russian state was to blame for the 4 March poison attack on Sergei Skripal and his daughter Yulia, which has left both in a critical condition.

Russia retaliated overnight, expelling British diplomats. The Kremlin has denied any involvement in the attack.

Bishop said Australia would support the UK in any move to send weapons inspectors into Russia to view its program, given Russia’s 1997 signature on the chemical weapons convention.

“Under the chemical weapons convention, one state that suspects another state of having illegal chemical weapons can seek these inspections and Britain certainly has the right to do that, and they are aware that we would support them, should they go down that path,” Bishop told the ABC.

“This is a situation that cannot be allowed to continue. One cannot have a permanent member of the security council, or indeed any country anywhere, any time, deploying illegal chemical weapons, and so clearly Britain is within its rights to take action, as it has done with expelling diplomats.

“Russia typically retaliates. But I have been in constant communication with [UK] foreign secretary Boris Johnson and Australia is most certainly considering what other options might be available.”

May has spoken in UK parliament to condemn Russia for the attack.

“On Monday I set out that Mr Skripal and his daughter were poisoned with a Novichok: a military grade nerve agent developed by Russia,” she told MPs in a statement last week.

“Based on this capability, combined with their record of conducting state sponsored assassinations – including against former intelligence officers whom they regard as legitimate targets – the UK government concluded it was highly likely that Russia was responsible for this reckless and despicable act.

“And there were only two plausible explanations.

“Either this was a direct act by the Russian state against our country.

“Or conceivably, the Russian government could have lost control of a military-grade nerve agent and allowed it to get into the hands of others.”

On Sunday, Bishop echoed May’s language and said Australia also believed Russia was either behind the attack or had lost control of its chemical weapons program.

“Russia is a party to the chemical weapons convention and under that chemical weapons convention, all chemical weapons should have been declared and it would appear that this nerve agent has not been declared,” she said.